Method for manufacturing a steering wheel

Abstract

The present invention relates to a method for manufacturing a steering wheel (1) comprising a frame (10), a cover (20) formed by a body (21) overmolded on the frame (10), and at least one insert (27), the method comprising the steps of providing at least one recess (22) in the cover (20) and manufacturing the insert (27) so that, upon assembly of the insert (27) with the body (21) of the cover, the insert (27) is able to at least partially cover the recess (22), characterized in that the insert (27) is obtained as an integral part of the body (21) of the cover.

Description

Technical Field

[0001] The present invention generally relates to the field of vehicles, and more specifically, to the field of steering wheels, such as, for example, steering wheels for automobiles.

[0002] A steering wheel typically consists of a frame including a hub, with spokes connecting the hub to a core or rim extending from the hub, and the core or rim forms the circular or substantially circular portion of the steering wheel. The frame forming the backbone or skeleton of the steering wheel can be obtained by injecting a light metal such as aluminum or magnesium under pressure. This frame can then be overmolded with a urethane foam obtained, for example, from a polyurethane elastomer (PU, PUR).

[0003] In the parlance commonly used by those skilled in the art, overmolding the frame results in a foaming operation of the steering wheel. This operation is generally carried out by placing the frame in a mold formed from two parts, one on top of the other. The mold has a steering wheel cavity that can be filled with a casting (one or more chemical substances in liquid form) injected under pressure through a supply channel under predetermined temperature and pressure conditions. Due to a chemical reaction, these conditions enable the casting material to change into a foam, solidify, and harden after a certain time to form a rough cover for the frame.

[0004] This cover will substantially cover the circular or substantially circular portion of the steering wheel, but may extend to the spokes. This cover will be trimmed, especially to remove excess foam cast around the steering wheel, when it comes out of the mold. Then, finally, the steering wheel may be covered by a sheath, for example, typically made of natural or artificial leather. This last operation is generally done manually by an operator who applies an adhesive to the cover, stretches, closes, and sews the leather sheath.

[0005] As is well known, steering wheels currently have control buttons, and often even sensors, for the purpose of improving safety during driving by facilitating access to specific functions without specifically leaving the steering wheel. These control buttons and other devices need to be powered and connected by wires hidden in channels left on the surface of the cover by the overmolding (foaming) operation of the frame, specifically within the steering wheel and more specifically within the cover of the steering wheel.

[0006] The problem caused by these channels is the fact that when the sheath is applied to the steering wheel, the wires placed in these channels can be felt through the sheath intentionally stretched to conform to the shape of the steering wheel. If the wires or cables protrude from the channels, or conversely, if they are set too far recessed from the surface of the cover or if they do not completely fill the channels in which they are placed, bulges or deformations may be felt after the application of the sheath.

[0007] Furthermore, due to the injection method and the movement of the two mold parts during the injection operation, the placement of the channels on the steering wheel is restricted, so the channels are not always placed in the least conspicuous locations. The position of the channels needs to allow for the demolding of the steering wheel and also maintain the minimum injection thickness.

[0008] From a functional perspective, it is important to fabricate the steering wheel well to avoid compromising user safety. However, the steering wheel should also have a comfortable feel, be aesthetically perfect, and be ergonomically designed for the driver's pleasure and comfort. In any case, the steering wheel constitutes an important element in the interface between the vehicle's steering mechanism and the driver. Prior Art

[0009] U.S. Patent Application Publication No. 2003 / 0075003 discloses a steering wheel that can give the impression of being formed in the pattern and texture of natural wood both visually and tactilely. In one embodiment, the cover of the steering wheel in this document is manufactured from two parts. The first part is a main part with a C-shaped cross-section that is inserted onto the core or rim of the frame. This first part constitutes the front surface of the cover. The second part is positioned on the back surface and includes an insert aimed at closing the C-shaped open part left by the first part. Summary of the Invention Problems to be Solved by the Invention

[0010] While considering improving the comfortable feel of the steering wheel for easier gripping by the driver, the prior art solutions cannot efficiently solve the problem of bulges or deformations caused by the sheath applied on the cover with recesses or channels made for arranging members such as electric wires inside.

[0011] Therefore, it is beneficial to find a more appropriate and efficient solution that can at least partially solve the aforementioned drawbacks.

[0012] Therefore, in one aspect, the present invention relates to a method for manufacturing a steering wheel including a frame, a cover formed by an overmolded body on the frame, and at least one insert, the method comprising: a step of providing at least one recess in the cover; a step of manufacturing the insert such that the recess can be at least partially covered by assembling the insert and the body of the cover, and characterized in that the insert is obtained as an integral part with the body of the cover.

[0013] Advantageously, the recess provided in the cover constitutes a space that can be partially occupied by one or more non-structural members such as electric wires. However, this space may also be completely occupied or empty. Regardless of the degree of occupancy or filling of the space by such members, it is possible to obtain a cover with a continuous or homogeneous surface by covering the space with the insert during assembly. Such a surface enables ensuring an optimal sheath without bulges, folds, dents, or other deformations when the sheath is applied and stretched over the cover.

[0014] More advantageously, this method for manufacturing the cover is particularly efficient in order to obtain the expected results while minimizing costs or labor. In fact, since the insert and the body of the cover are obtained as an integral part, it is possible to simultaneously obtain the overmolding of the frame and at least one insert associated with this overmolding, so that it is not necessary to obtain all the parts of the cover using more than two molding operations. More advantageously, it is not necessary to increase the channels for supplying the material injected into the mold. Since the body of the cover and the insert are integral parts, they are necessarily connected to each other and form one and the same cavity in the mold. Furthermore, since the insert is injected simultaneously with the remaining foam, it is possible to ensure that all elements due to the foam have the same flexibility and have similar injection characteristics. Also, it is advantageous that during handling or transportation of the steering wheel, it is impossible to forget the insert without it being deliberately removed from the main body of the cover. Finally, this enables the production of only one part, and thus only one part reference needs to be managed.

[0015] In a preferred embodiment, the insert is obtained by being attached to the main body of the cover by at least one attachment bridge.

[0016] In another embodiment, a recess is further provided in the peripheral part of the main body of the cover and / or the insert, and is configured to be able to receive the whole or a part of the attachment bridge therein.

[0017] According to one specific step of the method, the attachment bridge is removed from the insert and / or from the main body of the cover.

[0018] Furthermore, according to a preferred embodiment, the attachment bridge is inserted into the above-mentioned recess. For example, more specifically, the attachment bridge can be inserted into the recess by a movement consisting of pressing the insert against the main body of the cover and folding it. Preferably, in this case, the recess is provided in front of the attachment bridge. This embodiment makes it possible to limit the operation of cutting the bridge, thereby saving time and materials and avoiding managing scrap.

[0019] Preferably, the above-mentioned attachment bridge is arranged to form a hinge between the main body and the insert, and the manufacturing method includes the operation of inserting the insert into the recess by folding the attachment bridge forming the hinge. This embodiment eliminates the operation of cutting the attachment bridge, thereby simplifying the assembly operation.

[0020] Preferably, the recess is provided in the main body of the cover. However, this recess may be provided in the insert or even partly in the main body of the cover and partly in the insert. Thus, in one embodiment, the recess is provided at least partly in the insert.

[0021] More preferably, the indentation and / or the recess are obtained during the molding of the cover.

[0022] In one embodiment, the insert has a shape that at least partly matches the shape of the recess.

[0023] In one embodiment, the insert is at least partly inserted into the recess. This makes it possible to facilitate the placement of the insert and ensure better joining of the separate parts.

[0024] In one embodiment of the present invention, the method further includes placing at least one member in the recess before the assembly of the insert and the main body of the cover. Preferably, the member is an electrical member. Thus, according to this method, it is possible to integrate electrical members such as wires or a set of wires in the foaming of the steering wheel simply and with a high degree of design freedom.

[0025] In a preferred embodiment, the steering wheel comprises a plurality of inserts. By using a plurality of inserts, it is possible to cover a larger surface area of the cover while restricting the size of the injection mold due to the general curvature of the rim.

[0026] In one embodiment, one or more inserts are arranged as an integral part with the main body of the cover at the periphery of the cover during manufacture.

[0027] In one embodiment, the main body of the cover has a joint surface and the mounting bridge is arranged on the joint surface. This embodiment simplifies the design of the injection mold for the cover.

[0028] In other words, since the insert and the cover body are manufactured in the same process of the present method, they form an integral part. In other words, the insert and the cover body are made of the same material.

[0029] Therefore, when a single process of manufacturing the insert and the cover body is completed, a continuous part is obtained with the material between the insert and the cover body.

[0030] For example, when the manufacturing is performed by molding, at the outlet of the mold, the insert and the cover body are one and the same part, having a first part intended to form the insert and a second part intended to form the cover body, and both parts can be connected together, for example, by a bridge.

[0031] In a second aspect, the present invention relates to a steering wheel obtained by implementing the method according to any one of its embodiments, with respect to the first aspect of the present invention. Preferably, this second aspect relates to a steering wheel comprising a frame, a cover formed by an overmolded body on the frame and at least one insert, wherein the insert and the overmolded body of the cover are obtained as an integral part.

[0032] In one embodiment, one end of the insert is adjacent to a sheath groove of the cover. The sheath groove is of a hollow shape arranged to receive the seam of the sheath, and is made of, for example, natural leather or synthetic leather and adhered and / or sewn to the peripheral part of the cover. When the end of the insert is adjacent to such a groove, since the seam of the sheath is in this area, the risk of visibility of the joint is limited.

[0033] In one embodiment, the two ends of the insert are adjacent to two different sheath grooves of the cover.

[0034] In a third aspect, the present invention relates to a motor vehicle comprising a steering wheel according to the second aspect of the present invention.

[0035] In a fourth aspect, the present invention relates to an injection mold for carrying out a method according to any one of the embodiments of the method, or according to any one of the possible combinations of these embodiments, for the purpose of carrying out the method which is an object of the first aspect of the present invention.

Brief Description of the Drawings

[0036]

Figure 1

[0037]

Figure 2

[0038]

Figure 3

[0039]

Figure 4

Modes for Carrying Out the Invention

[0040] Figure 1 shows a plan view of a steering wheel 1 comprising a frame 10 and a cover 20. This steering wheel is typically obtained by overmolding the frame 10 with the cover 20. The frame 10 is made of an alloy or a light metal such as magnesium or aluminum and typically constitutes the support or skeleton of the steering wheel. This frame includes a hub 11 from which spokes 13 extend to connect the hub 11 to a core or rim 15. The rim constitutes a structural part that gives the steering wheel a circular or substantially circular shape.

[0041] The cover 20 consists essentially of a body 21 overmolded on the frame and at least one insert 27. At least a partial overmolding of the cover on the frame is obtained by molding. To do this, the frame 10 is placed in a mold having a cavity for the steering wheel 1. This mold is generally formed from two parts, typically an upper half and a lower half, and includes injection channels that allow a material such as urethane foam (PU, PUR) to be injected. The operation of molding the steering wheel, i.e., at least a partial overmolding of its frame, is also called foaming by those skilled in the art. The injected foam will solidify and then cure after a certain period of time and under certain temperature and pressure conditions.

[0042] In Figure 1, it can be seen that the cover 20 is formed from not only the body 21 but also at least one insert 27, preferably a plurality of inserts (in this example, four). These inserts 27 constitute the fitting parts of the cover body and are associated with the cover so that the cover can be completed.

[0043] The manufacturing method of the steering wheel of the present invention particularly aims at a step of providing at least one recess 22 in the cover 20, and The method includes a step of manufacturing the at least one insert 27 such that, by assembling the insert 27 and the main body 21 of the cover, the recess 22 can be at least partially covered.

[0044] According to the method of the present invention, the insert 27 is obtained as an integral part with the main body 21 of the cover. This feature is better shown in FIG. 2, which represents a perspective view of a part of the steering wheel 1, more specifically, a part of the steering wheel in front of one of the inserts 27.

[0045] The recess 22 (more visible in FIG. 2) will allow the placement of at least one member 32 within the main body 21 of the cover of the steering wheel. In the example of FIG. 1, this member 32 consists of, for example, an electric wire that can be connected to a control button 35 (FIG. 3) of the steering wheel 1, specifically a set of electric wires. Such a control button 35 may typically be used to control a vehicle device, for example, to activate an audio function, a remote wireless connection, a speed regulator, an in-vehicle computer, or any other device.

[0046] Advantageously, the recess 22 provided in the cover 20 can be either empty or occupied by at least one member 32 without causing an undesirable surface effect on the cover 20. In other words, it provides a space that can be partially or entirely occupied by at least one member 32. Therefore, for any sheath 41 (FIG. 4) applied and stretched over the cover 20, no deformations such as bulges, cracks, or creases will be felt.

[0047] More advantageously, as a result of the manufacturing method of the present invention, the above-mentioned advantages can be obtained more particularly efficiently. This result is obtained, in particular, from the fact that each insert 27 of the cover can be advantageously obtained as an integral part with the body of the frame during the overmolding of the frame, i.e., in one and the same operation. Further, no additional material injection is required to obtain the cover of the frame as an integral part. More advantageously, by obtaining this cover including the insert 27 that can be removed from the body 21 as an integral part, the transportation, handling, storage, and tracking of each element of the cover in the manufacturing line are facilitated. Typically, obtaining one insert (or a plurality of inserts) and the body as an integral part is achieved by molding.

[0048] In one embodiment, as shown by the example of FIG. 2, the insert 27 is obtained by being attached to the body 21 of the cover 20 by at least one mounting bridge 25. This bridge can be regarded as a transition element or a connecting element that enables obtaining the cover formed from the body 21 and at least one insert 27 connected to this body as an integral part. As shown in this figure, when manufacturing this insert together with this body, preferably, two mounting bridges 25 are used to attach each complementary part or insert 27 to the body of the cover. More preferably, the mounting bridge 25 has two ends, one adjacent to the body and the other adjacent to the insert. Alternatively, it would be possible to obtain a connecting bridge having three or more ends, for example, a Y-shaped mounting bridge including three ends, or an H-shaped mounting bridge having four ends. According to another alternative, if the above bridge is in the shape of an I and is simply a wire arranged longitudinally along the body and the insert connected thereto, it would also be possible to consider a mounting bridge having one end.

[0049] Furthermore, in one embodiment that can be best seen in FIG. 2, the recess 24 is made in the peripheral portion of the main body 21 and is configured to be able to accommodate the whole or a part of the mounting bridge 25 therein or to be inserted therein. It will be appreciated that preferably there are as many recesses 24 in the cover 20 as there are mounting bridges. This recess may have a shape complementary to the shape of the mounting bridge or may be a recess having a shape such that when the insert 27 is assembled on the main body 21 to cover at least the recess 22, the mounting bridge 25 is aligned (preferably freely) and integrated with the main body 21.

[0050] Alternatively, for a similar purpose, the recess 24 may be provided at the peripheral portion of the insert 27, and further may be provided partly at the peripheral portion of the main body 21 and partly at the peripheral portion of the insert 27.

[0051] In one embodiment, the method of the present invention further includes the step of removing the mounting bridge 25 from the insert 27 and / or from the main body 21 of the cover. In fact, several scenarios can be considered to enable the assembly of the insert 27 and the main body 21.

[0052] In the first scenario, the main body 21 can be removed from the mounting bridge 25, for example, by cutting the end of this bridge adjacent to the main body 21. In this first scenario, it is advantageous that the main body 21 includes a recess 24 that specifically enables it to receive the mounting bridge 25 that remains integral with the insert 27, so that it is not necessary to separate the mounting bridge 25 from the insert 27. Referring to FIG. 2, by cutting one end of each mounting bridge 25, in this case the end adjacent to the main body 21, the insert 27 can be released, and it should be noted that the insert can be placed against the main body 21 according to the illustration given by the arrow F in order to perform the assembly of the insert and the main body. To do this, the recess 24 is preferably provided to match the mounting bridge 25 that remains integral with the insert 27.

[0053] In the second scenario, the insert 27 can be removed from the mounting bridge 25, for example, by cutting the end of this bridge adjacent to the insert 27. In this second scenario, it would be possible to create a recess 24 in the body 21 at a position adjacent to the mounting bridge 25. Thus, these bridges can specifically be folded into these recesses 24 during subsequent operations of covering the steering wheel. Further, if necessary, each mounting bridge can be provided with a necking or a weak line to facilitate its folding by pressing it against the peripheral part of the cover body, typically in a corresponding recess.

[0054] In the third scenario, both the insert 27 and the body 21 can be removed from the mounting bridge 25. This operation typically requires two cuts to completely separate each mounting bridge 25. These mounting bridges will preferably be discarded, but nevertheless, if the above-mentioned recesses are provided in the cover body for that purpose, they can be inserted into the recesses 24.

[0055] It should be noted that in the fourth scenario, the insert 27 and the body 21 may not need to be removed from the mounting bridge 25. In this case, on the one hand, these bridges are arranged such that the insert can be folded or turned back onto the body 21 during the assembly of the insert with the body, and on the other hand, in this assembled position, each mounting bridge 25 can be at least partially received in a corresponding recess 24. Thus, there may be embodiments in which the mounting bridge 25 is inserted into the recess 24 by a movement consisting of, for example, pressing and folding or turning back the insert 27 against the cover body 21.

[0056] In one embodiment of this scenario, the mounting bridge 25 can be arranged to form a hinge between the body 21 and the insert 27, and the method will include the operation of inserting the insert 27 into the recess 22 by folding the mounting bridge that forms the hinge.

[0057] Each of these scenarios enables the assembly of the insert 27 and the body 21 such that the surface of the insert is located within the extension of the surface of the body. The same applies to the surface of the mounting bridge 25 with respect to the surface of the body 21, because in each of these scenarios, the mounting bridge can be inserted into the recess 24 provided for that purpose. Thus, the surfaces of the body, the insert, and, where applicable, the mounting bridge can advantageously be in a straight line with each other, so that after such assembly, when the subsequent operation of covering the steering wheel is performed, the cover 20 has a uniform or homogeneous surface that hides the recess 22 without leaving a deformation on the sheath.

[0058] Specifically, when the body 21 and the insert 27 have not been removed from the mounting bridge 25, it can be said that the recess 24 is preferably made in front of the mounting bridge so that the mounting bridge can be easily inserted into the recess during the assembly of the insert and the body of the cover.

[0059] Preferably, the recess 22 is provided in the body 21 of the cover. However, this recess 22 can also be provided in the insert 27, or partially in the body 21 and partially in the insert 27. For this reason, it can be said that the recess can be provided at least partially in the insert 27.

[0060] In one embodiment, the insert 27 is at least partially inserted into the recess 22. According to a preferred embodiment, the assembly of the insert and the body is performed by connection and / or bonding. To do this, the body of the cover and the insert may be further configured to be assembled with each other. For example, the insert 27 may have a shape that is at least partially complementary to the recess 22. Alternatively or additionally, the body 21 can include a blind hole 23 (FIGS. 1, 2, and 4) configured to receive an alignment pin or other protrusion 28 (FIG. 4) that is integral with the insert 27. The blind hole 23 can typically be provided on the host surface of the body 21 for the purpose of receiving the insert at the edge of the recess 22, as shown in FIG. 4. However, these blind holes can also be made in the insert, and the pins can also be made in a part of the body of the cover. Of course, other connecting means may be preferred for assembling the insert and the body. These complementary shapes make it possible to facilitate the placement of the insert and ensure a better joining of the separate parts.

[0061] Preferably, the recess 22 is obtained during the molding of the cover, i.e., during the foaming operation. Thus, advantageously, this recess can be obtained without the need for subsequent operations such as milling a part of the cover 20 to create a recess inside the cover 20, for example. More preferably, for the same reason, this also applies to the depression 24.

[0062] The method of the present invention may further include the step of disposing at least one member 32 in the recess 22 before assembling the insert with the body of the cover. Preferably, this member 32 is an electrical member and is typically one or more conductors or wires.

[0063] Also, in one embodiment, it may be said that the steering wheel 1 preferably comprises a plurality of inserts 27.

[0064] The method of the present invention may further include the step of covering the steering wheel 1, specifically the cover 20, after placing the member 32 in the recess 22 and proceeding with the assembly of the insert 27 and the body 21. More precisely, this covering step is for covering the cover or a part of the cover and is obtained using a sheath 41 (Figure 4). This sheath is typically extended around the cover 20, in other words, around the assembly of the insert 27 and the body 21, or around a part of this assembly. Such a sheath 41 will typically be manufactured from a flexible material such as leather, for example.

[0065] In another embodiment, before the step of covering with the sheath 41, another element such as a heating element or a presence sensor may be covered. The presence of such an element between the cover and the outer sheath makes it possible to hide any defects that may remain at the joint between the insert and the cover.

[0066] In a second aspect, the present invention also relates to the steering wheel 1 obtained by implementing the method of the first aspect, more specifically, the steering wheel 1 obtained by any one of the embodiments of this method or any one of the possible combinations of these embodiments. Preferably, this second aspect relates to a steering wheel 1 comprising a frame 10, a cover 20 formed by an overmolded body 21 and at least one insert 27 on this frame 10. According to the present invention, this steering wheel 1 is characterized in that the insert 27 and the overmolded body 21 of the cover 20 are integrally formed.

[0067] In a third aspect, the present invention relates to a vehicle, specifically to an automobile equipped with the steering wheel 1 according to the second aspect of the present invention.

[0068] In a last aspect, the present invention also relates to an injection molding die for implementing the method according to any one of the embodiments of this method or any one of the possible combinations of these embodiments.

Claims

1. A method for manufacturing a steering wheel (1) comprising a frame (10), a cover (20) formed by an overmolded body (21) and at least one insert (27) on the frame (10), comprising: A step of providing at least one recess (22) in the cover (20); A step of manufacturing the insert (27) such that the recess (22) can be at least partially covered by assembling the insert (27) and the body (21) of the cover; The insert (27) is made of the same material as the body (21) of the cover and is obtained as an integral part with the body (21) of the cover; The insert (27) is obtained by being attached to the body (21) of the cover by at least one attachment bridge (25); The method is characterized in that the attachment bridge (25) is removable from the insert (27) and / or from the body (21) of the cover.

2. The method according to claim 1, characterized in that a recessed portion (24) is further provided at the peripheral portion of the body (21) of the cover and / or at the peripheral portion of the insert (27), and is configured to receive the whole or a part of the attachment bridge (25) therein.

3. The method according to claim 2, further characterized in that the attachment bridge (25) is inserted into the recessed portion (24).

4. The method according to any one of claims 1 to 3, characterized in that the recess (22) is provided in the body (21) of the cover.

5. The method according to any one of claims 1 to 4, characterized in that the insert (27) has a shape that is at least partially complementary to the recess (22).

6. The method according to any one of claims 1 to 5, further comprising arranging at least one member (32) in the recess (22) before assembling the insert (27) and the body (21) of the cover.

7. The method according to claim 6, characterized in that the member (32) is an electrical member.

8. The method according to any one of claims 1 to 7, characterized in that the steering wheel (1) comprises a plurality of inserts (27).

9. The main body (21) of the cover has a joint surface, and the mounting bridge (25) is arranged on the joint surface, and the method according to claim 1, characterized in that.

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